Electronic Engine Control (EEC) System

Electronic Engine Control (EEC) System

Overview

The EEC system provides optimum control of the engine and transmission through the enhanced capability of the powertrain control module (PCM). The EEC system also has an on-board diagnostics (OBD) monitoring system with features and functions to meet federal regulations on exhaust emissions.

Note: Some vehicle applications use a stand alone transmission control module (TCM). While still part of the EEC system the TCM communicates to the PCM anti-lock brake system (ABS) module instrument cluster and four-wheel drive (4WD) control modules using the high speed CAN communication link. The TCM incorporates a stand alone OBD-II system. The TCM independently processes and stores fault codes freeze frame support PIDs as well as J1979 Mode 09 CALID and calibration verification number (CVN). The TCM does not directly illuminate the MIL but request the PCM to do so. The TCM is located inside the transmission assembly. It is not repairable with the exception of reprogramming.

Below is a list of transmissions that use a TCM:

^ F21 (FWD) transmission
^ ZF CFT3O (FWD) continuously variable transmission (CVT)
^ ZF 6IJP26 (RWD) transmission

The EEC system has 2 major divisions: hardware and sofiware. The hardware includes the PCM sensors switches actuators solenoids and interconnecting terminals. The software in the PCM provides the strategy control for outputs (engine hardware) based on the values of the inputs to the PCM. The EEC hardware and sofiware are discussed in this section.

This section contains detailed descriptions of the operation of the EEC system input sensors and switches output actuators solenoids relays and connector pins (including other power-ground signals).

The PCM receives information from a variety of sensor and switch inputs. Based on the strategy and calibration stored within the memory chip the PCM generates the appropriate output. The system is designed to minimize emissions and optimize fuel economy and driveability. The sofiware strategy controls the basic operation of the engine and transmission provides the OBD strategy controls the malfunction indicator lamp (MIL) communicates to the diagnostic tool via the data link connector (DLC) allows for flash electrically erasable programmable read only memory (EEPROM) provides idle air and fuel trim and controls failure mode effects management (FMEM)

Modifications to OBD Vehicles

Modifications or additions to the vehicle may cause incorrect operation of the OBD system. Anti-theft systems remote starters cellular telephones and CB radios must be carefully installed. Do not install these devices by tapping into or running wires close to powertrain control system wires or components.